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Java DelayQueue iterator()用法及代码示例


DelayQueue的iterator()方法用于在DelayQueue中的所有元素上返回迭代器。这些元素可以过期或未过期。

用法:

public Iterator iterator ()

参数:此方法不接受任何参数。


返回值:此方法返回此延迟队列中元素的迭代器。

下面的程序来说明Java中的DelayQueue iterator():

例:

// Java Program Demonstrate DelayQueue iterator() method 
  
import java.util.concurrent.*; 
import java.util.*; 
  
// The DelayObject for DelayQueue 
// It must implement Delayed and 
// its getDelay() and compareTo() method 
class DelayObject implements Delayed { 
  
    private String name; 
    private long time; 
  
    // Contructor of DelayObject 
    public DelayObject(String name, long delayTime) 
    { 
        this.name = name; 
        this.time = System.currentTimeMillis() 
                    + delayTime; 
    } 
  
    // Implementing getDelay() method of Delayed 
    @Override
    public long getDelay(TimeUnit unit) 
    { 
        long diff = time - System.currentTimeMillis(); 
        return unit.convert(diff, TimeUnit.MILLISECONDS); 
    } 
  
    // Implementing compareTo() method of Delayed 
    @Override
    public int compareTo(Delayed obj) 
    { 
        if (this.time < ((DelayObject)obj).time) { 
            return -1; 
        } 
        if (this.time > ((DelayObject)obj).time) { 
            return 1; 
        } 
        return 0; 
    } 
  
    // Implementing toString() method of Delayed 
    @Override
    public String toString() 
    { 
        return "\n{"
            + " " + name + ", time=" + time + "}"; 
    } 
} 
  
// Driver Class 
public class GFG { 
    public static void main(String[] args) throws InterruptedException 
    { 
  
        // create object of DelayQueue 
        // using DelayQueue() constructor 
        BlockingQueue<DelayObject> DQ 
            = new DelayQueue<DelayObject>(); 
  
        // Add numbers to end of DelayQueue 
        // using add() method 
        DQ.add(new DelayObject("A", 1)); 
        DQ.add(new DelayObject("B", 2)); 
        DQ.add(new DelayObject("C", 3)); 
        DQ.add(new DelayObject("D", 4)); 
  
        // Creating an iterator 
        Iterator val = DQ.iterator(); 
  
        // print the value after iterating DelayQueue 
        System.out.println("The iterator values are: "); 
        while (val.hasNext()) { 
            System.out.println(val.next()); 
        } 
    } 
}
输出:
The iterator values are: 

{ A, time=1545818784540}

{ B, time=1545818784541}

{ C, time=1545818784542}

{ D, time=1545818784543}


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注:本文由纯净天空筛选整理自ProgrammerAnvesh大神的英文原创作品 DelayQueue iterator() method in Java with Examples。非经特殊声明,原始代码版权归原作者所有,本译文未经允许或授权,请勿转载或复制。